Identifier

Author

Degree

Doctor of Philosophy (PhD)

Department

Kinesiology

Document Type

Dissertation

Abstract

Cardiovascular function is under the influence of autonomic nervous system, both of which can be assessed non-invasively. The purpose of this dissertation was to examine these non-invasive markers of cardiovascular and autonomic function and their relationships with exercise training, glucose ingestion and hydration status. A series of three studies were conducted to gain insight to various influences on cardiovascular and autonomic function. The first study examined the influence of exercise training of brachial artery flow-mediated dilation (BAFMD) using meta-analytic techniques. Sixty-six studies included in the analysis demonstrated exercise training improves BAFMD compared to controls. Results indicated exercise training significantly alters BAFMD, a well-known factor associated with prevention of cardiovascular diseases. Exercise training interventions including greater intensity and duration may optimize increases in BAFMD. The second study observed glucose ingestion alters autonomic nervous system function, shifting the sympathetic/parasympathetic balance to higher sympathetic activity. Higher exercise intensity decreased fasting heart rate variability 24-hrs after cessation of exercise whereas lower exercise intensity did not alter heart rate variability. Acute exercise increased heart rate variability after an oral glucose tolerance test, but was not affected by exercise intensity. The last study determined the effect of chronic dehydration on cardiovascular and sweat responses during exercise in a heated environment. Dehydration altered blood and urine markers of hydration status, but did not change cardiovascular and sweat response to exercise in the heat. . In addition, BAFMD was related to the change in weighted skin temperature and body temperature during exercise in the heat, and increased LF/HF at rest was associated with increased peak heat storage. Together these data suggest resting cardiovascular health may influence the ability to thermoregulate during exercise in the heat.